Hatching instrument for drawings



C. MULLER.

HATCHING INSTRUMENT FOR DRAWINGS.

APPLICATION FILED IEB. 24, 1920.

1,362,635, PIIIenIed Dec. 21,1920.

' 'CHARLES MLLER, OF ZURICH, SWITZERLAND.

HATCHVING INSTRUMENT FOR DRAWINGS.

Specification of Letters lateut.r Y Patented Dc, 21, 1920,

Application filed February 24, 1920. Serial No. 360,872.

To all whom it may concer/a Be it known that I, CHARLES lVItiLLnn,y a citizen of the Republic of' Switzerland, residing. at Zurich, ASwitzerland, have invented certain new and useful Improvements in Hatching `Instruments .for Drawings; and .l do hereby declare the following to be a clear, full, and exact description et the invention, such as vwill enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawing, and to letters or figures of reference marked thereon, which form a part ot this specification.

The present invention relates to drawing instruments and more particularly to instruments used for hatching parts oi drawings.

ln the accompanying drawing vwhich shows one mode of carrying this invention into efl'ect,

. Figure 1 is a plan,

Fig. 2 is a vertical section. of Fig. 1.

Fig. 3 shows the instrument connected to a T-square.

1 denotes a plate on which two friction wheels 4 and 5 are rotatably mounted on bolts 2 and 3 respectively, the wheels being provided with teeth on their for the purpose of .producing friction. The teeth of the wheels project over one of the longitudinal edges of plate 1. A ratchet wheel 6 is mounted on bolt 2, the ratchet along line lit- B wheel 6 and the friction wheel 4 being con-v nected to each other. by means ofa dowel pin 7 fixed in the toothed. wheel 4and projeeting into a hole of the ratchet wheel 6, the two wheels 4 and (Saturn together. Further a two-armed lever 8 is mounted on bolt 2 acting as fulcrum, which carries on one arm a spring loaded pawl 9 that is in engagement with the ratchet wheel 6, and n the other arm a tension spring 1() which tends to keep the opposite arm oi? the lever pressed against a stud 11. One .arm of the lever is bent upward and ends in a key 12, which projects above the upper longitudinal edge oi plate 1. 13 denotes a milled edge thumb screw mounted on the plate by which the stroke of the lever 8 can be regulated. Y

rlhe instrument described is shown. in Fig. 3 connected to a T-square 14, 15. It is screwed to the underside of the head 14 of a T-square by meansof screws going through against the head roundscrew 17 .circumference v referenceto the head. 14, so that the longitudinal edge of plate 1, overwhich the teeth or the wheelsf4 and 5 prOject, is flush rwith the inner edge of the head 14. The angle the hola; le of pia@ i and a'sp1ad,-Wah

between the edge of thel blade of the T- l square andtheinner edge of the head 14 can be altered and the two partsfixed against each other bymeans'of a clamping screw 1T. `A slot A18 is provided in the plate 1 for allowing screw `17 to pass through the plate 1.

In order to hatch a partof a 'drawing with this instrument fixed toth-e Tsquare', key 12 is to be pressed down after La line is drawn until the 'lever 8 rests set screw 13. Thereby .the wheel4 is turned by means ofthe pawl 9 engaging the ratchet wheel, which turning motion of wheel V4 causes part of .its circumference to roll on the edge of the drawing board, the teeth of the wheel penetrating into the. edge of the board and preventing any gliding. The

rolling motion. of the wheel 4 causes a par# allel. translation of the T`square and a new against vthe line rmayloedrawn on the drawing board. f

Theturning ofthe blade of the T-square toalmost any given angle allows of producinglhatch'- ings atialmost any angle with the horizontal line. The distance between the parallel lines can be altered by adjusting'the thumbscrew 13. Such an alteration-may also be attainedl by interchanging `ratchet wheely .6 with another of different pitch.

A spring loaded pawl 19, locking the ratchet wheel fwhen the lever is at rest, is provided on the-opposite side yof pawl `9', which prevents an unintended displacement of the T-square along the edge of the boardV in the direction 1n which pawl 9 does not l lock. Pawl 19 is brought out of engagement with the ratchet wheel when the key 12 is pressed down and the wheel is thus free to l the ratchet action caused by the pawl 9.

A hatching instrument present invention may be quickly and easily fixed to any Tsquare and a drawing of large dimensions may be hatched without damaging the drawing. tage over the hitherto known constructions, whereinV toothedV wheels or needle points work on the drawing itself and damage it. The new. instrument is not so easily dis: placed through inattention as the existing constructions, With the latter such disaccording to the i l10i; This is a great advanr on the placements occur very frequently because these instruments rest on the drawing and must be held in position by hand.

The known hatching instruments are moreover expensive and no large surfaces can be hatched with them, whereas the in- 'strument according to the invention is very simple in design and can be manufactured at a low price.

I claim: I

1. A lhatching instrument, comprising a plate adaptedto be fixed tothe underside of the head of a T-square, friction wheels mounted on said plate and adapted to engage with the edge of a drawing board., a ratchet wheel operatively connected to one of said friction wheels, a pawl engaging the ratchet wheel, a spring loaded lever acting pawl, and a key integral with the lever, eachrmovement of which causing a certain turn of the frictionwheels andv therefore a certain parallel translation of the parts to which the instrument may be connected.

2. A hatching instrument, comprising a plate adapted to be fixed to the underside of the head of a T-square, friction wheels mounted on said plate 'and adaptedfto engage with theedge of a drawing board, a ratchet wheel operatively connected to one a pawl engaging the ratchet-wheel, a two armed .lever Vcarrying the pawl, onek arm of the lever'being arranged as a key, each movement of which causing a certain turn of the friction wheels and therefore a certain parallel'translation lof the parts to which the instrument may be connected.

3. A hatching. instrument, comprising a.

plate adapted to be fixed to the underside of the head of a T square, friction wheels mounted on said plate and adapted to engage with the edge of a drawing board, a

ratchet wheel operatively connected to one of said friction wheels, a pawl engaging the ratchet wheel, a lever acting on the pawl, a -set screw, the adjustment of which limits the action of the lever on said pawl, and a key integral with fthe lever, each movement of which causing acertain turn of the friction wheels andtherefore a certain parallel translation .of the parts t0 which the instrument may be connected.

4. A hatching instrument, comprising a plate adapted to beV fixed to the underside ofthe head of a T-square, friction wheels mounted on saidplateand adapted to engage with the edge of .a drawing board, an interchangeable ratchet wheel operatively connected to one of'said friction wheels, a pawi engaging the ratchet wheel, a `lever acting on the pawl and a key integral with the lever, each movement of which causing a certain turn of the friction wheels and therefore a certain parallel translation of the parts to which the instrument may be connected. Y

y5. A hatching instrument, comprising a plate adapted to be 'fixed to the underside of the head of a T-square, friction wheels mounted on said plate and adapted to engage with the edge of a drawing board, an interchangeable ratchet wheel operatively connected to one of said friction wheels, a pawl engaging the ratchet wheel, a two armed lever provided with a key, a paWl fixed to one arm of the lever and engaging with said ratchet wheel, and a second pawl fixedV to the other arm of said lever, each movement of the key causing a certain turn of the friction wheels and therefore a certain parallel translation of the parts to which the instrument may be connected.

6..A hatching instrument comprising a plate for connection to the head' ofy a'*T- square, a rotatable .friction member mounted CHARLES MLLER. 

